Telephone-exchange system.



Patented Apr. 2,2, i902.

un. 693,087.v

H. GLWEBSTER. TELEPHONE EXCHNGE SYSTEM.

(Applicgtionle Feb. 25, 1901.)

(No Model.)

UNITED -STATES PATENT OFFICE.

HARRY G. WEBSTER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE STROMBERG- CARLSON TELEPHONE MANUFACTURING COMPANY, OF CHICAGO,'ILLI- NOIS, A CORPORATION OF ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 698,087, datedkApril 22, 1902.

Application filed February 25, 1901- Serial No. 48,716.- (No model.)

To all whom it may concern.- Be it known that I, HARRY G.WEBSTER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephone-Exchange` Systems, (Case No. 3,) of which the following is a full, clear, concise, and exact description, reference being had to the accompanying draw- Io ings, forming a part of this specification.

My invention relates to telephone-exchan ge systems, and has for its object the provision of improved means wherebya subscriber who fails to restore his receiver to its switch-hook I5 after conversation isfinished may be signaled tov remind `him of the fact. In accordance with my invention this service is preferably performedby an loperator who makes this one of his special duties, the switching operator zo being thus relieved of this work. In accordance with my invention I provide means whereby this special operator may send a signal through the cord-circuit that has been employed for connecting the subscriber for conversation to produce a vibration in the subscribers receiver, this being accomplished through the agency, preferably, of an alternating current, so that a humming noise is produced in the subscribers receiver that 3o Will serve to attract his attention.

I employ as the source of currentfor thus actuating the subscribers receiver the common battery that is employed in the common-battery systems for supplying the transmitters at the 3 5 subscribers stations with current. This commou ybattery is included in a subsidiary circuit that extends to the signaling-operators desk, this subsidiary circuitpreferably including a make-and-break device and the prilv 4o mary of an induction-coil, whereby alternat-v ing current is produced, anoperating-key being also lincluded inthis circuitltoclose the same when it is desired to transmit the signali-ng-current. The secondary of the induction-coil` is included in circuit withy a plug thatis adapted 'for insertion within a trunking-jack that extends to the desk of theoperator that switches lines into and out of connection. To simplify the apparatus, the same y cord-circuit that is used to unite subscribers the trunk-line las a continuation of the line of theV subscriber who has failed to restore his receiver, the plugy that is used for connecting this trunking-line having been removed from the jack of thesubscriber who has restored his telephone.

f I will explain my invention more fully by reference to the accompanying drawing,that' 'v i illustrates a single telephone-line extending to an exchange, with instrumentalities at the" exchange for continuing this telephone-line to the desk of the operator, who may effect i i an actuation of the receiver at the substation illustrated. 1 f

In this partici'ilarinstance I haveshown one type of. telephone substation apparatus,

primary coil e to the upper contact of the switch-hook and also through the bell f t'o the lower contact of the switch-hook. Thereceiver is shown included in a local circuit with the secondary g in inductive relation with the primary e.

b and c extend; vbut the invention obviously A multiple switchboard is illustrated, to the jackso'f which the limbs is applicable ytoiall forms oftelephone-ex` f change systems. The switching-operators cord-circuit isshown with theanswering-plug h inthe answering-jack of, thesubscriber,

the connecting-plug 1I having been` lremoved'A from vthe jack of thecalled subscriber, who

is considered' to have properly restored rhis telephone to its switch-hookfand inserte'dw'1 `within the trunking-jack cfor'fthe pu'rfposegj-v 7.

y I i1 1.90 Theoperatorscord-circuitis equipped with the usual listening-key Zandringing-key Y Y bymeansof which instrumentalities the op`- erator may bridge her telephone set-"n .be-f y' 95 to be more fully explained.,-

tween the strands of the cord-circuit to'ia's'- certain the condition of use of the telephone-` v ,v

5 for conversation is also used for connecting line and to signal the subscriber. A clearing-out indicator o is illustrated, that is connected across the telephone-circuit, a common battery p being included in this same cross connection, the clearingout indicator being of sufficient impedance to prevent a shunting of the voice-currents. It will be observed that this clearing-out indicator, when the cord-circuit is employed to connect two subscribers for conversation, is included in a bridge of the united telephone-lines, so that the clearing-out signal will not be given until both subscribers have restored their telephones. By means of the listening-key the operator may test the condition of the line from time to time, the clearing-out indicator not conveying a clearing-out signal, and if no conversation is being carried on and she gets no response to her inquiry as to whether or not the parties are engaged in conversation she withdraws one plug or the other, keeping that plug in the jack of the line that is still in closed circuit with the clearing-out indicator and placing the companion plug in the trunking-jack extending to the chief-operators jack q. Any suitable means may be employed for notifying the chief operator. l have illustrated a signal fr, included in circuit with springs of the jack q, which circuit is opened when the chief operator plugs into his tru nk-line jack. A special cord-circuit provided with a single plug s and a connected telephone may be employed to enable the chief operator to receive word from the switching operator. The chief operator is provided with a signaling-plug t, provided with a loop-cord circuit, including the secondary u, across the limbs of the subscribers telephone-line. The subsidiary circuit, including the generator, extends from the common battery to the chief-operators desk. This subsidiary circuit includes the chief-operators signaling-key fu, and also includes a circuit-breaking magnet fw, the armature of the said magnet being included in series with its coil in the said subsidiary circuit, the armature in one position serving to close the circuit and in the alternate position to open the same. To prevent injurious sparking between the armature and its contact, a condenser is included in shunt about the said armature and contact. The primary'y is included in this subsidiary circuit and is in inductive relation to the secondary. The chief operator to effect the actuation of the diaphragm of the subscriber-s receiver operates the signaling-key lv, whereby the continuous current from the battery p is transformed into an alternating current, which is conveyed by induction through the secondary coil, chief-operators plug and trunking-jack, the truuk-line between the chief-operators desk and the switching-operato1"s desk, the jack of the switching-operators desk and the inserted plug, and thence by the cord-circuit through thejack of the subscribers line and the plug inserted therein to the primary of the induction-coil at the subscribers station, and thence by induction through the closed circuit including the subscribers receiver.

Having thus described my invention, I claim as new and desire to secure by Letters Patentl. In a com mon-battery telephone-exchange system, the combination with a subscribers line extending from the substation to an exchange, the said substation being provided with a telephone receiver and transmitter, of a common battery at the exchange connected with the said telephone-line and serving to supply the transmitter at the subscribers station with current, a subsidiary circuit in cluding the said common battery, means for creating in the said subsidiary circuit a signaling-current that is adapted to operate the diaphragm of the receiver at the subscribers station to produce a calling-signal, and means for directing this current over the telephone* line, substantially as described.

2. In a common-battery telephone-exchange system, the combination with a subscribers line extending from a substation to an exchange, the said substation being provided with a telephone receiver and transmitter, of a common battery at the exchange connected with the said telephone-line and serving to supply the transmitter at the subscribers station with current, a local subsidiary circuit including the said common battery, means for creating from the battery a signaling-current in the said subsidiary circuit, a primary coil included in the subsidiary circuit, a sec; ondary coil for the said primary, and means for including the vsecondary coil in circuit with the subscriberis telephone-line, whereby the receiver at thc said substation may be operated to give a signal if it is oil its hook, substantially as described.

3. Inacommon-battery telephone-exchange system, the combination with a snbscribers `line extending from a substation to an eX- change, the said substation being provided with atelephone receiver and transmitter, of a common battery at the exchange connected with the said telephone-line and serving to supply the transmitter at the subscribers station with current, a local subsidiary circuit including the said common battery, means for creating a signaling-current in the said subsidiary circuit, a primary coil included in the subsidiary circuit, a secondary coil for the said primary, a trunk-line extending between a chief operator and the switching operator, a jack and plug for connecting the secondary coil with the said trunk-line at the chief-operators desk, a jack at the switching-operators desk also connected with the said trunksline, and an operators cord-cirnecting the said jack with the jack of the iid said subscriber, whereby the signaling-cur- In witness whereof-lrhereunto subscribe rent created inthe saidsubsidiary local cir-I my name this 19th day of February, A. D. cuit is passed over the trunk-line through the 1901.

sWitching-operators cord-circuit to the sub- `HARRY \G. WEBSTER. station to operate the diaphragm of the re- Witnesses: ceiver at .the said substation if the receiver is C. J. STONE,

off its hook, substantially as described. E. E. ALDEN. 

